Sucrase-isomaltase deficiency

Sucrase-Isomaltase Deficiency: Background and Overview

Sucrase-isomaltase deficiency (SIID), also known as congenital sucrose-isomaltase deficiency, is a rare hereditary disorder caused by the lack of one of the intestinal enzymes necessary for the digestion of carbohydrates. This disorder, which is one of the few diseases of carbohydrate malabsorption, specifically affects the digestion of foods containing sucrose, which is composed of glucose and fructose. Many symptoms of this disorder occur after consuming foods with sucrose.

When SIID is present, the body cannot absorb sufficient amounts of carbohydrates from sucrose-containing foods. This malabsorption can lead to abdominal cramping, bloating, and diarrhea. Other symptoms can include gastrointestinal discomfort and poor growth. Treatment of SIID can include dietary restrictions, nutrition, and vitamin supplementation.

Types of Sucrase-Isomaltase Deficiency

There are two primary types of SIID, type I and type II. In type I SIID, the lack of enzyme activity is caused by mutations in the SI gene, which is located on chromosome 3. This type of SIID is characterized by severe malabsorption of carbohydrates and poor growth. In type II SIID, the lack of enzyme activity is caused by mutations in the SIS gene, located on chromosome 2. This type of SIID is more moderate and is characterized by moderately impaired sielectrolyte malabsorption. Both types of SIID can cause gastrointestinal issues, poor growth, and vitamin deficiencies.

Diagnosis and Treatment of Sucrase-Isomaltase Deficiency

The diagnosis of SIID is made by testing for specific enzyme activity in the small intestine. Treatment for SIID is typically dietary in nature and involves avoiding foods that contain dietary sucrose. Additionally, vitamin and mineral supplementation may be recommended. In some cases, enzyme replacement therapy with oral enzymes may be used. Due to its rarity, little information is available about long-term outcomes of SIID.

Conclusion

Sucrase-isomaltase deficiency is a rare hereditary disorder caused by the lack of one of the intestinal enzymes necessary for the digestion of carbohydrates. This disorder can lead to gastrointestinal discomfort, poor growth, and vitamin deficiencies. Treatment of SIID typically involves dietary modifications, vitamin and mineral supplementation, and possibly enzyme replacement therapy. Further research is needed to make more definitive treatment recommendations for this rare disorder.